Medium severity · published Oct 12, 2026
CVE-2026-109299
Open WebUI 0.9.0 before 0.11.4 Denial of Service via Recurrence Rule Validation
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
Open WebUI from 0.9.0 before 0.11.4 contains a denial of service vulnerability that allows authenticated users with automations permission to stall the instance by submitting unsatisfiable recurrence rules. Attackers can repeatedly send rules like February 30th to the automations create or update endpoints, blocking the shared event loop for seconds per request.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
open-webui · open-webui
0.9.0 before 0.11.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-109299
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-109299
vendor-advisory
https://github.com/open-webui/open-webui/security/advisories/GHSA-5w58-mwmh-vf2m
patch
https://github.com/open-webui/open-webui/commit/5fb869db221d9599a576e8e2eea9c3314947d25e
third-party-advisory
https://www.vulncheck.com/advisories/open-webui-0.9.0-before-0.11.4-denial-of-service-via-recurrence-rule-validation
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